@ViewChild

@ViewChild can access only local template of component, not parent or child components.

@Component({
  selector: 'app-login',
  template: `
<re-captcha></re-captcha>
<div #refname></div>
`,
  styleUrls: ['./login.component.css']
})
export class LoginComponent implements OnInit, AfterViewInit {
 
  @ViewChild(RecaptchaComponent) reCaptcha: RecaptchaComponent;
  @ViewChild('refname') input: ElementRef;
 
  constructor() {
    console.log(this.reCaptcha); // null
  }
 
  ngAfterViewInit(): void {
    console.log(this.reCaptcha); // not null
  }
 
}